Heatsink and heatsink device using the heatsink

ABSTRACT

A heatsink and a heatsink device using the heatsink are provided. The heatsink is formed of a plurality of thin heatsink plates, and the individual heatsink plates are bound to one another to be radially spread out, thereby enlarging the surface area of the heatsink and increasing its heat-dissipating efficiency. In the heatsink device, the heatsink is installed in an air duct, and cool air is supplied into the air duct by a fan, to thereby further increase the heat-dissipating efficiency. The binding force of the heatsink to a heat-generating source can be elastically maintained, which allows the heatsink to remain bound to the heat-generating source even after an external impact. In addition, by cutting out an upper portion of the heatsink plate, folding lines of the heatsink plate are shortened so that the heat-absorbing portions of the heatsink plates stacked upon one another can be tightly joined to form a heatsink by a reduced force. The resulting heatsink has a recession at the center of its upper surface. This structure allows cool air propelled by the fan to reach the bottom center of the heatsink, thereby further enhancing the heat-dissipating efficiency. Also, vibration and noise caused while cool air flows over the heat-dissipating portions of the heatsink are reduced.

This file is a Division of Ser. No. 10/086,368 filed Mar. 4, 2002 nowU.S. Pat. No. 6,712,127.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a heatsink and a heatsink device usingthe heatsink, and more particularly, to a heatsink having a very largeheat dissipating surface area, which is formed of a plurality of thinheatsink plates, and a heatsink device in which the heatsink isinstalled in an air duct, so that air generated by a fan is guided intothe air duct to increase heat dissipating efficiency, and the force withwhich the heatsink is pressed against a heat-generating source can beelastically maintained.

2. Description of the Related Art

Heatsinks serve as cooling device for heat generating objects such aselectronic components or devices, by absorbing heat generated by suchobjects and dissipating the absorbed heat into the air. Electroniccomponents such as central processing units (CPUs), thermoelectricelements, video graphics array (VGA) cards, and power transistorsgenerate a large amount of heat during operation. When the temperatureof an electronic component exceeds a certain level, the electroniccomponent may malfunction or outright fail in the worst case. For thisreason, a heatsink is often required to be installed at a heatgenerating source to dissipate heat into air.

With the rapid development of science and technology, a variety ofelectronic components or devices have been highly integrated andminiaturized in recent years. As a consequence, techniques forincreasing the surface area of heat dissipating fins as much as possibleand shortening the heat conducting pathway in heatsinks have beensuggested. By these techniques, the dimensions of heatsinks can bereduced with increased heat dissipating efficiency. However, in aconventional manufacturing process, the heat dissipating fins of aconventional heatsink cannot be made thin enough to increase the heatdissipating efficiency. In addition, the cost of manufacturing byconventional methods is high.

Heatsinks are commonly installed along with a fan to increase the heatdissipating efficiency. For example, a fan is installed on a heatsink,and blows air over the heatsink, thereby by cooling the heatsink.Although cool air is blown at the heatsink by a fan, most of it isdeflected away, so a very small amount of the cool air is used forcooling. In consideration of the increasing need for high-performanceand highly integrated electronic components, which generate a largeamount of heat during operation, there is a need for an effectivecooling mechanism capable of sufficiently dissipating the heat generatedfrom such electronic components.

SUMMARY OF THE INVENTION

To address the above limitations, it is an object of the presentinvention to provide a heatsink with increased heat dissipatingefficiency, in which a plurality of thin heatsink plates, which arearranged in a stack, are tightly joined to one another such that theyare radially spread out, so that the heat conducting pathway becomesshort with increased heat dissipating surface area.

It is another object of the present invention to provide a heatsinkdevice using the heatsink, in which the heatsink is installed in an airduct and air from a fan is guided into the air duct to further increasethe heat dissipating efficiency.

It is still another object of the present invention to provide aheatsink device in which the binding force between the heatsink and aheat-generating source can be elastically adjusted, so that the heatsinkflatly contacts the entire surface of the heat-generating source, andthe heatsink remains bound to the heat-generating source even after anexternal impact.

To achieve the objects of the present invention, there is provided aheatsink for absorbing heat generated from a heat-generating source, theheatsink being in contact with the heat-generating source, anddissipating the absorbed heat into the air, the heatsink comprising: aplurality of sheet-shaped heatsink plates each having a heat-absorbingportion in contact with the upper surface of the heat-generating sourceand substantially normal thereto to absorb heat from the heat-generatingsource, and a heat-dissipating portion extending from the heat-absorbingportion to dissipate the absorbed heat into the air, wherein theplurality of heatsink plates are arranged in a stack, the heat-absorbingportions of the individual heatsink plates are tightly joined to oneanother, so that the heat-absorbing portions form the center of thestack of the heatsink and the heat-dissipating portions of theindividual heatsink plates are radially spread out from the center togive the heatsink an elliptical column form.

In one embodiment, the present invention provides a heatsink comprising:a plurality of sheet-shaped heatsink plates each having a heat-absorbingportion in contact with the upper surface of a heat-generating sourceand substantially normal thereto to absorb heat from the heat-generatingsource, and a heat-dissipating portion extending from the heat-absorbingportion to dissipate the absorbed heat into the air, the upper portionof each of the heatsink plates being cut out into a predetermined shapesuch that the resulting upper contour slants downward from theheat-dissipating portion toward the heat-absorbing portion, wherein theplurality of heatsink plates are arranged in a stack, the heat-absorbingportions of the individual heatsink plates are tightly joined to oneanother by a pair of compression blocks, so that the heat-absorbingportions form the center of the heatsink and the heat-dissipatingportions of the individual heatsink plates are radially spread out fromthe center to give the heatsink an elliptical column form having arecessed upper center.

To achieve the objects described above, the present invention alsoprovides a heatsink device comprising: a heatsink including a pluralityof sheet-shaped heatsink plates each having a heat-absorbing portion incontact with the upper surface of the heat-generating source and normalthereto to absorb heat from the heat-generating source, and aheat-dissipating portion extending from the heat-absorbing portion todissipate the absorbed heat into the air, wherein the plurality ofheatsink plates are arranged in a stack, the heat-absorbing portions ofthe individual heatsink plates are tightly joined to one another, sothat the heat-absorbing portions form the center of the heatsink and theheat-dissipating portions of the individual heatsink plates are radiallyspread out from the center to give the heatsink an elliptical columnform; an air duct in which the heatsink is installed to guide cool airover the heatsink, the air duct having a height smaller than theheatsink to allow a predetermined gap between the lower end of the airduct and a printed circuit board; and a fan installed on the air ductfor forcibly cooling the heatsink by blowing air into the air duct.

Alternatively, the heatsink device according to the present inventioncomprises: a mount casing coupled onto a socket frame which surrounds aheat-generating source mounted on a printed circuit board and hascoupling supports protruding from its circumference, the mount casinghaving a coupling leg detachably coupled to each of the couplingsupports of the socket frame and an air duct at its center to allow theflow of cool air therein; a heatsink installed in the air duct incontact with the upper surface of the heat-generating source todissipate heat from the heat-generating source; an elastic compressionmember which elastically pushes the heatsink toward the heat-generatingsource while being supported by the mount casing; and a fan mounted onthe mount casing to blow the cool air into the air duct.

BRIEF DESCRIPTION OF THE DRAWINGS

The above objects and advantages of the present invention will becomemore apparent by describing in detail preferred embodiments thereof withreference to the attached drawings in which:

FIG. 1 is a perspective view of a first preferred embodiment of aheatsink device according to the present invention, which is mounted ona printed circuit board (PCB);

FIG. 2 is an exploded view showing the structure of the heatsink deviceof FIG.

FIG. 3 is an exploded view of an example of a heatsink applicable to theheatsink device of FIG. 1, in which only a few heatsink plates areshown;

FIG. 4 is a plan view showing a state where the heatsink plates arestacked and compression blocks are brought in contact with the stack;

FIG. 5A is a partially cutaway perspective view of a complete heatsink,which is assembled as illustrated in FIG. 3;

FIG. 5B is an inverted perspective view of the heatsink of FIG. 5A;

FIG. 6 is an exploded view of another example of the heatsink applicableto the heatsink device of FIG. 1, in which only a few heatsink platesare shown;

FIG. 7 is a plan view showing a state where the heatsink plates andspacers are alternately stacked to one upon the other, as illustrated inFIG. 6, and compression blocks are brought into contact with the stack;

FIG. 8A is a sectional view of an example of an elastic coupler of theheatsink device of FIG. 1, which elastically couples the heatsink deviceto a PCB;

FIG. 8B is a sectional view of another example of the elastic coupler ofthe heatsink device of FIG. 1, which elastically couples the heatsinkdevice to a PCB;

FIG. 9 is a partially cutaway perspective view illustrating theoperation of the heatsink device of FIG. 1, and a method of mounting theheatsink device on a PCB;

FIG. 10 is a perspective view of an example of a heatsink applicable toa second preferred embodiment of the heatsink device according to thepresent invention;

FIG. 11 is an inverted perspective view of the heatsink of FIG. 10;

FIG. 12 shows a single heatsink plate of the heatsink of FIG. 10;

FIG. 13 is an exploded view of the heatsink of FIG. 10, in which a fewheatsink plates are shown;

FIG. 14 illustrates the heat dissipating mechanism of the heatsink ofFIG. 10;

FIG. 15 is an exploded perspective view illustrating an example of theuse of the heatsink of FIG. 10;

FIG. 16 shows another example of a single heatsink plate of the heatsinkapplicable to a heatsink device according to the second preferredembodiment of the present invention;

FIG. 17 is a partially cutaway perspective view of a complete heatsinkcomprising a number of heatsink plates having the structure shown inFIG. 16;

FIG. 18 is an exploded perspective view illustrating the structure of aheatsink device according to the second preferred embodiment of thepresent invention;

FIG. 19 is a perspective view of the coupling structure of a mountcasing to a socket frame in the heatsink device of FIG. 18;

FIG. 20 is a perspective view illustrating the heatsink being coupled tothe mount casing to assemble the heatsink device of FIG. 18;

FIG. 21 is a partially cutaway perspective view of the second embodimentof the heatsink device according to the present invention; and

FIG. 22 is a partially cutaway perspective view of another heatsinkdevice according to the second embodiment of the present invention towhich the heatsink of FIG. 17 is applied.

DETAILED DESCRIPTION OF THE INVENTION

A heatsink according to the present invention is formed by stacking aplurality of thin heatsink plates, and tightly joining the same to oneanother such that they are radially spread out to increase the surfacearea of the heatsink. As a result, the heat conducting pathway of theheatsink becomes short with increased heat dissipating surface area,thereby increasing heat dissipating efficiency. A heatsink deviceaccording to the present invention comprises an air duct in which theheatsink is installed so that cool air generated by a fan can be guidedover the heatsink, thereby further increasing the heat dissipatingefficiency. In addition, by elastically supporting the heatsink withrespect to a heat-generating source, so that the heatsink can remainbound to the heat-generating source even after an external impact.

FIG. 1 is a perspective view of a preferred embodiment of the heatsinkdevice according to the present invention, which is mounted on a printedcircuit board (PCB). As shown in FIG. 1, the heatsink device 11dissipates heat generated by an electronic component, such as a centralprocessing unit (CPU), in a state where the heatsink device 11 issupported with respect to a PCB “C” on which the heat generatingelectronic component is mounted.

The heatsink device 11 includes a heatsink 35 in an elliptical columnform, which is to be placed in contact with the top of an electroniccomponent “H” (also referred to as a heat-generating source) beingnormal thereto (see FIG. 2), an air duct 15 in which the heatsink 35 isinstalled, and a fan 13 installed atop the air duct 15.

An auxiliary duct 21 may be interleaved between the air duct 15 and thefan 13 as needed. The auxiliary duct 21 seals the gap between thecircumference of the air duct 15 and the housing of the fan 13 to guidecool air from the fan 13 into the air duct 15 without air leaking. Inthe present embodiment, the auxiliary duct 21 is formed like a gasket,as shown in FIG. 2.

The height h1 (see FIG. 2) of the heatsink 35 is greater than the heighth2 (see FIG. 2) of the air duct 15. As a result, when the fan 13 isfixed to the top of the air duct 15, and the heatsink 35 is installed inthe air duct 15, a lower portion of the heatsink 35 protrudes outwardwith respect to the air duct 15 by a height difference h1−h2. That is,the lower portion of the air duct 15 is spaced apart from the PCB “C” bythe height difference h1−h2.

The gap between the air duct 15 and the PCB “C” serves as an air pathway19 to allow air to flow into and out of the air duct 15 when the fan 13is operated. For example, if the fan 13 is operated such that air issucked up from the air duct 15, air enters the air duct 15 through theair pathway 19. If the fan 13 is operated such that air is forced intothe air duct, air from the fan 13 passes through the heatsink 35 andexits the air duct 15 through the air pathway 19.

Eight vertical through holes 29 and 30 are formed in pairs on the outercircumference of the air duct 15 An elastic coupler, which applies anelastic force to the PCB “C” and allows the air duct 15 to remain on andnormal to the PCB “C” by the elastic force, is installed at eachvertical through hole 29 or 30.

The elastic coupler applies a predetermined elastic force to the PCB “C”to ensure tight contact between the heatsink 35 and the heat-generatingsource “H”. The elastic coupler keeps the heatsink 35 in tight contactwith the entire surface of the heat-generating source “H” being normalthereto, and holds the heat-generating source “H” in place even after astrong impact is applied. This elastic coupler will be described laterwith reference to FIGS. 8A and 8B.

FIG. 2 is an exploded view showing the structure of the heatsink deviceof FIG. 1. Referring to FIG. 2, the heatsink device 11 includes theheatsink 35 having an elliptical column form, which is to be mounted onthe heat-generating source “H”, the air duct 15 which is elasticallysupported with respect to the PCB “C” being normal thereto and in whichthe heatsink 35 is installed, the auxiliary duct 21 installed on the airconduct 15, and a fan 13 fixed to the top of the auxiliary duct 21.

The heatsink 35 having an elliptical column form is manufactured bytightly joining the heat-absorbing portions 73 (see FIG. 3) of aplurality of heatsink plates 16 and 17, which are arranged in a stack,such that the heat-dissipating portions 75 (see FIG. 3) are radiallyspread out. The heat-absorbing portions 73 of the individual heatsinkplates form the center of the heatsink, and the heat-dissipatingportions 75 extends outward from the heat-absorbing portions 73, to givethe heatsink an elliptical column form. The bottom of the heatsink 35 isbrought in contact with the upper surface of the heat-generating source“H” being normal thereto, so that heat generated by the heat-generatingsource “H” is transferred to the surface of the individual heatsinkplates 16 and 17 in the upward and radial directions.

Reference numeral 37 denotes a compression block. As shown in FIG. 3,the compression block 37 is formed as a trapezoidal column. The twocompression blocks 37 are placed close to the heat-absorbing portions 73(see FIG. 3) of the stack of heatsink plates 16 and 17, and pushedinward to tightly join the heat-absorbing portions 73 to one another.The compression blocks 39 may be formed as rectangular columns, ratherthan trapezoidal columns, in terms of productivity. In this case, acompression force stronger than for the trapezoidal compression blocksis required to spread out the heat-dissipating portions 75. Thestructure of the heatsink 35, and a method for manufacturing theheatsink 35 will be described in greater detail later with reference toFIGS. 3 through 7.

A pair of heatsink-clamping columns 90 protrude from the innercircumference of the air duct 15 facing each other, and two holes 41 areformed in each of the heatsink-clamping columns 90 in a longitudinaldirection. Four clamping screws 23 are inserted into the air duct 15 ina lateral direction through the holes 41 and screwed into respectivescrew holes 53 (see FIG. 5A) of the compression block 37 of the heatsink35. As each of the clamping screws 23 is screwed into the correspondingscrew hole 53 through the corresponding hole 41, the heatsink 35 istightly fixed to the air duct 15.

The auxiliary duct 21 seated on the air duct 15 seals the gap betweenthe fan 13 and the circumference of the air duct 15 to prevent leakageof air propelled by the fan 13, as shown in FIG. 9. Alternatively, theauxiliary duct 21 and the air duct 15 can be formed as a single unit.For example, when a plastic injection technique is applied to form theair duct 15, it is preferable that the auxiliary duct and the air duct15 are formed as a single unit.

The auxiliary duct 21 is formed as a flat member having a circular holeat its center, and the rim of the auxiliary duct 21, which is conformalto the top contour of the air duct 15, has four screw holes 45. Thecentral circular hole of the auxiliary duct 21 corresponds to an airpathway of the fan 13.

Four screw holes 43 are formed at the top surface of the air duct 15.Four screws 77 are screwed into the screw holes 43 through the edge ofthe fan 13 and corresponding screw holes 45 of the auxiliary duct 21, sothat the fan 13 is fastened to the air duct 15.

The vertical through holes 29 and 30 are formed in pairs at fourlocations on the outer circumference of the air duct 15. A hold downscrew 25, a spring 67 which is slid over the hold down screw 25, and acoupling rod 31 coupled to the hold down screw 25, are inserted intoeach vertical through hole 29 or 30. As shown in FIG. 8A, a supportprojection 69 is formed on the inner wall of each of the verticalthrough holes 29 and 30. The ends of the coupling rod 31 and the holddown screw 25 are coupled within each vertical through hole 29 or 30.The spring 67 elastically supports the hold down screw 25 upward againstthe support projection 69 (see FIG. 8A).

The coupling rod 31 having a cylindrical form has a screw hole 33 at oneend, and a support head 39 at the other end. The coupling rod 31 isinserted into each assembly hole 49 or 50 of the PCB “C”, from thebottom to the top of the PCB “C”, and pushed upward. At this time, thesupport head 39 of the coupling rod 31 remains at the bottom of the PCB“C” and supports the PCB “C” upward. As the hold down screw 25 isscrewed into the screw hole 33 of the coupling rod 31, the air duct 15is elastically bound to the PCB “C” by an elastic force of the spring67.

Although a pair of the vertical through holes 29 and 30 are formed atfour locations around the air duct 15 in the illustrated embodiment, itwill be appreciated that more vertical through holes can be formedaround the air duct 15. The vertical through holes 29 and 30 of the airduct 15 are positioned corresponding to the assembly holes 49 and 50formed in the PCB “C”, respectively. The inner assembly holes 49correspond to the assembly holes formed in a PC motherboard comprisingthe Via KT133 chipset for AMD CPU's. The outer assembly holes 50correspond to the assembly holes formed in, for example, motherboardsmade for Intel's Pentium 4 CPU. The vertical through holes 29, which arecloser to the air duct 15 than the vertical through holes 30 are, matchthe inner assembly holes 49, and the vertical through holes 30 match theouter assembly holes 50. Thus, the heatsink device according to thepresent invention can be applied to both types of motherboards.Furthermore, the heatsink device according to the present invention canbe applied to any PCB, whose size and specifications differ from the twoboards described previously, by varying the shape of the circumferenceof the air duct 15.

FIG. 3 is an exploded view of an example of a heatsink applicable to theheatsink device of FIG. 1, in which a few heatsink plates are shown.Referring to FIG. 3, the heatsink includes a plurality of heatsinkplates 16 and 17, and two compression blocks 37 for tightly joining theplurality of heatsink plates 16 and 17 to one another. The individualheatsink plates 16 and 17 are heat-dissipating fins made of thinsheet-metal. The heatsink plates 16 and 17, and heatsink plates 154 and180 (see FIGS. 12 and 16), which are described later with respect to asecond embodiment of the present invention, can be formed of a knownmetal having good thermal conductivity, such as copper (Cu), aluminum(Al) or an Al alloy. The heatsink plates 16, 17, 154, and 180 may beformed of silver (Ag) as needed.

Each of the heatsink plates 16 and 17 includes a heat-absorbing portion73, and a heat-dissipating portion 75 extending from the heat-absorbingportion 73. Four holes 59 are formed in the heat-absorbing portion 73 ina longitudinal direction. Two of the four holes 59 are for coupling withthe air duct 15, as described with reference to FIG. 2. Thus, if onlythe heatsink 35 without the air duct 15 is installed on aheat-generating source, just two holes 59 can be formed in each of theheat-absorbing portions 73 in a longitudinal direction. The lower edgesof the heat-absorbing portions 73, which form a contact surface 61 withthe top of the heat-generating source “H”, are flat to ensure tightcontact with the entire top of the heat-generating source 47, as shownin FIG. 5B.

To the two neighboring heatsink plates 16 and 17, as shown in FIG. 3,the heat-dissipating portion 75 of the heatsink plate 16 extends fromthe heat-absorbing portion 73 on the right, whereas the heat-dissipatingportion 75 of the heatsink plate 17 extends on the left. Thus, as theplurality of the heatsink plates 16 and 17 are alternately stacked, theheat-dissipating portions 75 of the heatsink plates 16 and 17 extend ina staggered fashion, i.e., alternately on the right and left.

The side edge of the heat-absorbing portion 73 of each of the heatsinkplates 16 and 17 is folded by a predetermined width to form a foldedportion 57. The folded portion 57, which has a predetermined thickness,provides a space between neighboring heatsink plates 16 and 17. As acompression force is applied to the heat-absorbing portions 73 of thestack of heatsink plates 16 and 17, each having the folded portion 57,by the compression blocks 37 in contact with the heat-absorbing portions73 of the outermost heatsink plates 16 and 17, the heat-dissipatingportions 75 of the individual heatsink plates 16 and 17 are radiallyspread out by a force exerted upon the folded portions 57, resulting ina cylindrical heatsink 35, as shown in FIGS. 5A and 5B.

The heat-dissipating portions 75 of the individual heatsink plates 16and 17 are spread out a predetermined distance from each other. Theheat-dissipating portions 75 are spread out by a distance related to thethickness of the folded portions 57 as the heat-absorbing portions 73 ofthe stack of individual heatsink plates 16 and 17 are tightened by thecompression force. Although the heat-absorbing portion 73 is folded oncein the illustrated embodiment, it will be appreciated that theheat-absorbing portion 73 may be folded two or three times.

The compression blocks 37 compress the stack of heatsink plates 16 and17 in contact with the heat-absorbing portions 73 of the outermostheatsink plates 16 and 17. Each of the compression blocks 37 has twoscrew holes 53 into which the clamping screws 23 (see FIG. 2) arescrewed, and two through holes 51, which communicate with two holes 59of the heatsink plates 16 and 17 and are used to combine the compressionblocks 37 with the heatsink plates 16 and 17.

To tighten the individual heatsink plates 16 and 17 arranged in a stackwith the compression blocks 37, bolts or rivets can be used. Afterinserting bolts (not shown) through the through holes 51 of acompression block 37 and the holes 59 of the heatsink plates 16 and 17,the bolts protruding out from the through holes 51 of the othercompression block 37 are screwed into nuts (not shown), so that theindividual heatsink plates 16 and 17 are combined with the compressionblocks 37. Alternatively, after inserting common rivets (not shown)through the through holes 51 of a compression block 37 and the holes 59of the heatsink plates 16 and 17, the ends of the rivets projecting outfrom the through holes 51 of the other compression block 37 are hit toform rivet heads, thereby resulting in a complete heatsink.

FIG. 4 is a plan view showing a state where the heatsink plates 16 and17 are stacked, as illustrated in FIG. 3, and the compression blocks 37are brought in contact with the stack. Referring to FIG. 4, each of theheatsink plates 16 and 17 has the folded portion 57, and the individualheatsink plates 16 and 17 are spaced apart a distance related to thethickness of the folded portion 57. As the compression blocks 37 incontact with the outermost heatsink plates 16 and 17 are pushed indirection F, the heat-dissipating portions 75 of the heatsink plates 16and 17 are spread out to form a complete heatsink, as illustrated inFIGS. 5A and 5B.

FIG. 5A is a partially cutaway perspective view of a complete heatsink,which is assembled as illustrated in FIGS. 3 and 4, and FIG. 5B is aninverted perspective view of the heatsink of FIG. 5A. As shown in FIGS.5A and 5B, the heat-absorbing portions of the heatsink plates 16 and 17are compressed and bound to one another by the compression blocks 37.The compression blocks 37 are pushed by as strong a force as possiblesuch that the compression blocks 37 become closer to each other, andfixed to the heat-absorbing portions 73 of the heatsink plates 16 and17, so that the heat-dissipating portions 75 of the individual heatsinkplates 16 and 17 are radially spread out.

Reference numeral 55 denotes a bolt serving as a binding means of thecompression blocks 37. Although the bolt 55 is used as a binding meansin the illustrated embodiment, it will be appreciated that a known rivetor other binding means can be used instead of the bolt 55 to bind thecompression blocks 37 to the heatsink plates 16 and 17. Although thecompression blocks 37 have an indentation (not shown) around each of thethrough holes 51 in the illustrated embodiment to receive the heads ofthe bolts 55, as shown in FIG. 5A, the compression blocks 37 may bedesigned so that the heads of the binding means protrude outward tosimplify the manufacturing process.

As shown in FIG. 5B, the heat-absorbing portion of the heatsink 35 atthe bottom is made flat to ensure tight contact with the entire surfaceof the heat-generating source “H”.

FIG. 6 is an exploded view of another example of the heatsink applicableto the heatsink device of FIG. 1, in which only a few heatsink platesare shown. Elements having the same function as in FIG. 3 are denoted bythe same reference numerals. Referring to FIG. 6, the heatsink includesa plurality of stacked heatsink plates 18, a plurality of spacers 63,each of which is interposed between neighboring heatsink plates 18, anda pair of compression blocks 37 for tightly joining the heatsink plates18 to one another.

The heatsink plates 18 are formed of thin sheet-metal. The same materialused to form the heatsink plates 16 and 17 of FIG. 3 can be selected toform the heatsink plates 18. Each of the heatsink plates 18 has aheat-absorbing portion 73 at the center, and a pair of heat-dissipatingportions 75 which symmetrically extend from the heat-absorbing portion73. The heat-absorbing portion 73 and the corresponding pair ofheat-dissipating portions 75 are formed as a single body. Four holes 59are formed in the heat-absorbing portion 73 in a longitudinal direction.Two of the four holes 59 are for coupling with the air duct 15, as inthe previous embodiment described with reference to FIG. 3.

The spacers 63 are formed of thin sheet-metal, and the size of a singlespacer corresponds to the size of the heat-absorbing portion 73. Bothside edges of each of the spacers 63 are folded to form folded portions65. The folded portions 65 are parallel to each other. The role of thefolded portions 65 is the same as the role of the folded portions 57 ofFIG. 3. As the compression blocks 37 are pushed such that thecompression blocks 37 become closer to each other in a state where thestack of heatsink plates 18 and spacers 63 is placed therebetween, aforce exerted upon the folded portions 57 is transferred to theheat-dissipating portions 75 of neighboring heatsink plates 18, so thatthe heat-dissipating portions 75 of the individual heatsink plates 18are radially spread out, as shown in FIGS. 5A and 5B.

FIG. 7 is a plan view showing a state where the heatsink plates 18 andthe spacers 63 are alternately stacked upon one another, as illustratedin FIG. 6, before compression by the compression blocks 37 to form acomplete heatsink. Referring to FIG. 7, the individual heatsink plates18 are spaced apart a predetermined distance from each other by thespacers 63. Since each of the spacers 63 is folded once, the distancebetween neighboring heatsink plates 18 is twice the thickness of asingle spacer 63. The spacers 73 may be folded more than once.

As the compression blocks 37 are brought in contact with theheat-absorbing portions 73 of the outermost heatsink plates 18, and arepushed into the stack of heatsink plates 18 and spacers 63, theheat-dissipating portions 75 extending from the heat-absorbing portions73 radially spread out by a force exerted upon the folded portions 65.

FIG. 8A is a sectional view of an example of an elastic coupler of theheatsink device of FIG. 1, which elastically couples the heatsink deviceto a PCB. As previously described, the air duct 15 of the heatsinkdevice according to a preferred embodiment of the present, invention iselectrically supported with respect to the PCB “C” by an elasticcoupler. Accordingly, although the air duct 15 is moved upward by astrong impact, the air duct 15 immediately returns to its initialposition on the PCB “C” (see FIG. 1) and thus the heatsink 35 therein iskept in contact with and normal to the entire surface of theheat-generating source.

Referring to FIG. 8A, a support projection 69 is formed on the innerwall of each of the vertical through holes 29 and 30, which are formedaround the air duct 15. The support projection 69 supports the spring 67upward in each of the vertical through holes 29 or 30. A coupling rod31; a hold down screw 25, and a spring 67, which supports the hold downscrew 25 upward, are inserted into each of the vertical through holes 29or 30. A vertical movement of the heatsink device is guided along thevertical through holes 29 and 30 by the coupling rods 31 which contactthe inner wall of the vertical through holes 29 or 30.

The coupling rod 31 has a support head 39 and a screw hole 33 at itsends. The coupling rod 31 is inserted into each of the vertical throughholes 29 or 30 through the corresponding assembly holes 49 or 50 of thePCB “C”, from the bottom to the top of the PCB “C”. The PCB “C” issupported by the support head 39 which remains at the bottom of the PCB“C”.

The hold down screw 25 is inserted downward into each of the verticalthrough holes 29 or 30 to screw into the screw hole 33 of thecorresponding coupling rod 31. At this time, the spring 67 is slid overthe hold down screw 25, and then the hold down screw 25 is inserted intothe vertical through hole 29 or 30, so that the head 71 of the holdingdown screw 25 is supported by the spring 67 against the supportprojection 69, as shown in FIG. 8A. As the hold down screw 25 isinserted further into the coupling rod 31, the spring 67 is wellcompressed, increasing an upward support force with respect to the PCB“C” by the support head 39. Because the support head 39 of the couplingrod 31 remains at the bottom of the PCB “C”, the support force of thesupport head 39, which is exerted in direction K, becomes stronger asthe hold down screw 25 is tightened more and more.

The support force of the support head 39 with respect to the PCB “C” canbe controlled by adjusting the degree to which the hold down screw 25 istightened. The support force afforded by the support heads 39 is equalto the binding force of the heatsink 35 to the heat-generating source“H”. Thus, the binding force between the heatsink 35 and theheat-generating source “H” can be adjusted by varying the degree towhich the hold down screws 25 are tightened.

The support force is retained as the elastic force of the springs 67. Asa result, even if an external impact is applied to the PCB “C”, theimpact is absorbed by the springs 67 and thus not transferred to theheat-generating source “H”.

FIG. 8B is a sectional view of another example of the elastic coupler ofthe heatsink device of FIG. 1, which elastically couples the heatsinkdevice to a PCB. The structure of this elastic coupler is different fromthe elastic coupler of FIG. 8A. As long as an elastic force can beapplied to the air duct 15 against the PCB “C”, the structure of theelastic coupler can be varied.

As shown in FIG. 8B, a support projection 85 is formed on the inner wallof each vertical through hole 29 a or 30 a formed around the air duct15. Hold down screws 91 are inserted downward into the vertical throughholes 29 a and 30 a. Each hold down screw 91 passes through the verticalthrough holes 29 a or 30 a, protruding out of the air duct 15, as shownin FIG. 8B. The spring 67 is supported against the support projection85, and the head 71 of the hold down screw 91 is elastically supportedby the spring 67.

A coupling member 81 is placed below the air duct 15, facing the holddown screw 91. The coupling member 81 is formed as a cylinder havingscrew holes 83 at both ends, which are aligned with each other and intowhich the hold down screw 91 and a support screw 79 will be screwed,respectively. The support screw 79 is a round-headed screw. The oppositeend to the round head of the support screw 79 is inserted into theassembly hole 49 or 50 of the PCB “C”, from the bottom to the top of thePCB “C”, and screwed into one of the screw holes 83 of the couplingmember 81. The diameter of a round head of the support screw 79 islarger than the inner diameter of the assembly hole 49 or 50, so thatthe edge of the assembly hole 49 or 50 can be elastically pushed upwardby the head of the support screw 79.

In the elastic coupler having the configuration described above, theelastic support strength of the PCB “C” with respect to the air duct 15can be controlled by adjusting the degree to which the hold down screw91 or the support screw 79 is tightened into the coupling member 81.

FIG. 9 is a partially cutaway perspective view illustrating theoperation of the heatsink device, and a method of mounting the heatsinkdevice on a PCB. Referring to FIG. 9, the air duct 15 is mounted on topof the PCB “C” and normal thereto, and the auxiliary duct 21 and the fan13 are mounted atop the air duct 15. As described previously, theauxiliary duct 21 seals the gap between the circumference of the airduct 15 and the fan 13. The air duct 15 is supported by the coupling rod31 and the hold down screw 25 such that the air duct 15 contacts the PCB“C” and is normal thereto.

In this state, as the fan 13 is operated, air enters into the air duct15 through the fan 13 to cool the heatsink 35, and flows out of the airduct 15 through the air pathway 19 between the air duct 15 and the PCB“C”. As described previously, the lower end of the air duct 15 and thePCB “C” are spaced apart a predetermined distance from each other, sothat the air used to cool the heatsink 35 can easily exit the air duct15 through the air pathway 19.

Since the path of cool air from the fan 13 is isolated from the outsideby the air duct 15 and the auxiliary duct 21, the air can be sucked upfrom the air duct 15 by operating the fan 13 in an opposite direction.In this case, the air enters the air duct 15 through the air pathway 19to cool the heatsink 35 and exits upward through the fan 13.

Although, in FIG. 9, an elastic coupler is installed in each of theinner vertical through holes 29, the elastic coupler can be installed inthe outer vertical through holes 30 to cool an electronic componentmounted on a motherboard for Intel's Pentium 4 CPU.

FIG. 10 is a perspective view of an example of a heatsink applicable toa second preferred embodiment of the heatsink device according to thepresent invention. The cylindrical heatsink is characterized by having arecessed center at its upper surface to guide cool air propelled by thefan to the lower end of the heatsink, thereby further enhancing thecooling efficiency.

As is apparent from FIG. 10, in the present embodiment, the heatsink 150has an elliptical column form with a recession at the center of itsupper surface. The recessed center of the upper surface of the heatsinkis for guiding an increased amount of cool air from the fan toward thelower center of the heatsink. The bottom of the heatsink 150 isprocessed to be flat, as illustrated in FIG. 11, to increase the area ofcontact between the heatsink 150 and the heat-generating source “H”.

The heatsink 150 is formed by tightly joining a number of heatsinkplates 154, each having the shape illustrated in FIG. 12, which arestacked upon one another, with a pair of compression blocks 152. Aplurality of holes 166 (see FIG. 13) through which screws or rivets passare formed in each of the compression blocks 152. The principle ofassembling the individual heatsink plates 154 using the compressionblocks 152 is the same as described in the first embodiment according tothe present invention. Reference numeral 252 denotes a slot, which willbe described later.

FIG. 11 is an inverted perspective view of the heatsink 150 of FIG. 10.As shown in FIG. 11, the heatsink 150 has a flat bottom surface totightly contact a heat-generating source. As is well known, the degreeto which a heatsink tightly contacts a heat-generating source directlyaffects the heat-dissipating efficiency of the heatsink. Accordingly, itis desirable to increase the flatness of the bottom of the heatsink asmuch as possible. The bottom of the heatsink 150 may be processed bymeans of additional machining to improve the flatness of the bottom, ifrequired.

FIG. 12 shows a single heatsink plate of the heatsink of FIG. 10. Asshown in FIG. 12, each heatsink plate 154 is formed by cutting out anupper portion (the hatched portion “A” in FIG. 12) of a substantiallyrectangular piece of sheet-metal. The heatsink plate 154 has aheat-absorbing portion 156 at the center and a pair of heat-dissipatingportions 158 which symmetrically extend from the heat-absorbing portion156. The heat-absorbing portion 156 has two holes 160 in a longitudinaldirection and contacts a heat-generating source to absorb heat generatedtherefrom. The heat-dissipating portions 158 externally dissipate heatabsorbed by the heat-absorbing portion 156.

The heatsink plate 154 is manufactured by cutting out an upper portion,i.e., the hatched portion “A”, from the heatsink plate 18 of theembodiment according to the present invention shown in FIG. 6.Accordingly, the heatsink plate 154 is lighter than the heatsink plate18 by the weight of the hatched portion “A”. An upper contour 170 of theheatsink plate 154 slants from the heat-dissipating portions 158 locatedon both sides of the heat-absorbing portion 156 toward the center of theheat-absorbing portion 156 and then sharply rises upward on bothsidelines of the heat-absorbing portion 156, resulting in a symmetricalstreamline form.

The height “h” of the heat-absorbing portion 156 may be varied. Forexample, the height “h” of the heat-absorbing portion 156 can beextended to be equal to the height of the heat-dissipating portions 158.Alternatively, the heat-absorbing portion 156 can have no upperextension, as shown in FIG. 16.

By cutting out the upper portion of the heatsink plate 154 as describedabove, folding lines B′ of the heatsink plate 154 become shorter by halfor greater, than in the heatsink plate 18 described in the firstembodiment of the present invention. Thus, the individual heatsinkplates 154 can be tightly joined into the heatsink 150 with a reducedforce.

In FIG. 12, reference numeral 122 denotes folded portions. The foldedportions 122 are formed to enable the heat-dissipating portions 158 tobe radially spread out when the heat-absorbing portions 156 arecompressed by the compression blocks 152. The folded portions 122 areformed at both outer sides of and parallel to the folding lines B′ bypressing.

In particular, to form the folded portions 122, a predetermined portionof each heatsink plate 154 on each side of the heat-absorbing portion156 is incised in a bracket pattern, bent back and attached to the planeof the heatsink plate 154. Since the thickness of the heatsink plate 154at the folded portions 122 is greater than that at the remainingportions and the folded portions 122 are formed along the folding lineB′, the heat-dissipating portions 158 of the individual heatsink plates154 are radially spread out by a force exerted on the folded portions122 as the heat-absorbing portions 156 of the stacked heatsink plates154 are tightly joined to one another, as shown in FIG. 10.

FIG. 13 is a perspective view of the heatsink of FIG. 10, in which a fewheatsink plates are shown. As shown in FIG. 13, each heatsink plate 154is provided with a plurality of folded portions 122. The folded portions122 are formed to have the same function for the same purpose as thefolded portion 57 (see FIG. 3) described in the first embodimentaccording to the present invention. The folded portions 122 provide aforce enabling the heat-dissipating portions 158 of the individualheatsink plates 154 to be radially spread out as the heat-absorbingportions 156 of the stack of the heatsink plates 154 are pushed inopposite directions by the compression blocks 152.

FIG. 14 is a view of the heatsink from the direction indicated by arrow“A” of FIG. 10 to illustrate the heat dissipating mechanism of theheatsink. Referring to FIG. 14, heat generated from the heat-generatingsource “H” and absorbed by each heat-absorbing portion 156 of theheatsink 150 is transferred upward and outward, as indicated by arrows“a”. When the plurality of heatsink plates 154 are combined together,the cut-out portions of the heatsink plates 154 provide a space 164. Theempty space 164 provides a path for cool air propelled by the fan 128 totravel to the heat-generating source “H” without resistance.

Cool air from the fan 128 mostly flows downward, as indicated by arrows“b”, through the space 164 and the space formed between each of theheat-dissipating portions 158 which are radially spread out, and reachesthe heat-generating source “H”. The remaining portion of the cool airflows along the outer circumference of the heatsink 150, hits the innerwall of an air duct 228, and reaches the heat-dissipating portions 158to cool the same.

FIG. 15 an exploded perspective view illustrating an example of the useof the heatsink of FIG. 10. As shown in FIG. 15, the heatsink 150 ismounted into the air duct 228. The heatsink 150 is enclosed within theair duct 228 and close to its inner circumference. The upper centerportion of the heatsink 150 is recessed by the space 164. The air duct228 constitutes a second embodiment of the heatsink device according tothe present invention, which is described later, together with theheatsink 150.

The fan 128 is mounted on the heatsink 150. The fan 128 blows cool airdownward over the heatsink 150 while being fixed to the top surface ofthe air duct 228. In this state, when air propelled by the fan 128 flowsdownward toward the heatsink 150, as indicated by arrows “b”, the air isprevented from surging into the outer circumference of the heatsink 150.This is because the heatsink 150 has an almost uniform distribution ofresistance to the flow of air over the entire body. Rather, the airstream downward tends to flow toward the lower center due to thepresence of the space 164. This increased flow of the cool air towardthe lower center of the heatsink 50 enhances the heat-dissipatingefficiency.

FIG. 16 shows another example of a single heatsink plate of a heatsinkapplicable to the second embodiment of the heatsink device according tothe present invention. Elements having the same function as thosedescribed above are denoted by the same reference numerals. As shown inFIG. 16, the heatsink plate 180 has no extension from the heat-absorbingportion 156 located in the middle of the heatsink plate 180. An uppercontour 171′ of the heatsink plate 180 slants from the heat-dissipatingportions 158 located on both sides of the heat-absorbing portion 156,and horizontally extends from both sidelines of the heat-absorbingportion to form a top end.

The heatsink plate 180 is formed by cutting out a hatched portion “A”from the heatsink plate 18 (see FIG. 6) described in the firstembodiment according to the present invention such that a space 164 (seeFIG. 17) can be formed at the upper surface of a heatsink 182 assembledfrom a number of heatsink plates 180, as shown in FIG. 17.

FIG. 17 is a partially cutaway perspective view of a complete heatsinkformed of a number of heatsink plates having the structure of FIG. 16.The heatsink 182 induces the same flow of air as the heatsink 150 ofFIG. 15 to increase the heat dissipating efficiency. Referring to FIG.17, the heatsink 182 has a cylinder-like shape and has a space 164formed by its recessed upper surface. The space 164 has the samefunction as the heatsink 150 of FIG. 15.

The heatsink 182 is formed by tightly compressing a number of heatsinkplates 180, which are stacked upon one another, with the compressionblocks 152 so that the individual heat-dissipating portions 158 areradially spread out.

The heatsink for a heatsink device according to the second embodiment ofthe present invention has a recessed upper surface so that air propelledby the fan can mostly flow toward the center, rather than the outersides, of the heatsink to thereby increase the heat dissipatingefficiency. Also, each heatsink plate has short folding lines so that areduced compression force is required to tightly join a number ofheatsink plates at the heat-absorbing portions.

It will be appreciated that the shape of the heatsink plate can bevaried as long as the heatsink has a recessed upper surface.

FIG. 18 is an exploded perspective view showing the structure of aheatsink device according to the second embodiment of the presentinvention. Referring to FIG. 18, the heatsink device 210 includes amount casing 212 coupled to a socket frame 214, which has been fixed toa PCB “C”, the heatsink 150 of FIG. 10 installed in the mount casing212, and a plate spring 218 which elastically pushes the upper center ofthe heatsink 150 downward with respect to the mount casing 212. A fan128 is mounted on the mount casing 212 and blows air down over theheatsink 150.

The socket frame 214 is a known rectangular frame fixed to the PCB “C”to surround a heat-generating source “H” to be cooled. The socket frame214 has four coupling supports 262 extending upward from its fourcorners. Each coupling support 262 has a support bar 222 at its upperend, which provides a horizontal support base, and a rectangularcoupling hole 224 below the support bar 222.

The mount casing 212 is mounted on the socket frame 214 and has an airduct 228 at the center to accommodate the heatsink 150 therein and fourcoupling legs 226 at its corners.

Each coupling leg 226 is coupled to a corresponding coupling support 262of the socket frame 214 and has a support protrusion 230 and a couplingprotrusion 232. As shown in FIG. 19, the support protrusion 230 issupported upward by the support bar 222 of the coupling support 262. Thecoupling protrusion 232 is a toothed protrusion inserted into thecoupling hole 224.

The air duct 228, which accommodates the heatsink 150 therein, is spaceda predetermined distance above the PCB “C” while being coupled to thesocket frame 214, as shown in FIG. 19, thereby resulting in an airpathway below its bottom end to discharge air through the same. To thisend, the height h1 of the air duct 228 is determined to be smaller thanthe height h2 of the heatsink 150.

Basically, the inner circumference of the air duct 228 is formed to beconformal with the outer circumference of the heatsink 150 so thatalmost all the air from the fan 128 can be used for thermal exchangewith the heatsink plates 154 before exiting from the air duct 228.

The air duct 228 has a pair of heatsink-clamping columns 236 protrudingfrom its inner circumference and facing each other. Theheatsink-clamping columns 236 vertically formed on the innercircumference of the air duct 228 have the same size and contact therespective compression blocks 152, as shown in FIG. 21.

One of the heatsink-clamping columns 236 has a hole 249 at its upperportion. The hole 249 laterally extends to the outside through the airduct 228, and a clamping screw 220 described later passes through thehole 249.

The other heatsink-clamping column 236 has a screw hole 250 at its upperportion. The screw hole 250 whose inner wall is threaded is formedaligned with the hole 249. The clamping screw 220 passes through thehole 249 and is screwed into the screw hole 250 across the air duct 228.

A plate spring receptacle 238 is formed in each upper surface of theheatsink-clamping columns 236. The two plate spring receptacles 238 haveflat surfaces to receive both ends of the plate spring 218 thereon andvertical screw holes 240. The plate spring 218 will be described later.

The compression blocks 152 bound to both sides of the heatsink 150correspond to the respective heat-sink clamping columns 236, as shown inFIG. 21. Each compression block 152 protrudes above the top surface 260of the stack of the heat-absorbing portions 156. In other words, the topend of the compression block 152 is higher than the top surface 260 ofthe stack of the heat-absorbing portions 156.

Each compression block 152 has a slot 252 through its upper sides. Theslot 252 is slightly long in the vertical direction and is aligned withand communicates with the hole 249 and the screw hole 250 of eachheatsink-clamping column 236.

Since the slots 252, the hole 249, and the screw hole 250 are formedaligned with one another, the clamping screw 220 inserted into the hole249 of one heatsink-clamping column 236 can engage the screw hole 250 ofthe other heatsink-clamping column 236 through the slot 252 of onecompression block 152, across the top surface 260 of the stack of theheat-absorbing portions 156, and then through the slot 252 of the othercompression block 152.

The plate spring 218 is mounted on the upper surface of the heatsink150. The plate spring 218 is a bar-like member having a predeterminedwidth and thickness, and both ends of the plate spring 218 are seated onthe plate spring receptacles 238. The plate spring 218 has a middleportion bent downward to elastically push the top surface 260 of thestack of the heat-absorbing portions 156.

The middle portion of the plate spring 218, which is bent downward andV-shaped, forms an elastic compression portion 254. Slots 256 are formedin both sloping sides of the elastic compression portion 254. The slots256 are formed to be slightly long in the length direction of the platespring 218 and pass the clamping screw 220.

Both ends of the plate spring 218 have coupling holes 257 and are fixedto the respective plate spring receptacles 238 by screws 258. The screws258 engage the vertical screw holes 240 through the coupling holes 257of the plate spring 218.

After fitting the mount casing 212 to the socket frame 214, the heatsink150 is placed inside the air duct 228 such that the bottom surface ofthe heatsink 150 contacts a heat-generating source “H”. In this state,when the plate spring 218 is connected to the mount casing 212 by thescrews 258, the center of the heatsink 150 is elastically pusheddownward with respect to the mount casing 212 so that the bottom surfaceof the heatsink 150 elastically contacts the heat-generating source “H”.

In this state, the heatsink 150 is just placed inside the mount casing212, not coupled to the mount casing 212, while being elastically pusheddownward. As a result, when the mount casing 212 is dissembled from thesocket frame 214 and lifted up, the heatsink 150 stays on theheat-generating source “H”.

The clamping screw 220 connects the heatsink 150 to the mount casing212. The clamping screw 220 has a threaded end and engages the screwhole 250 formed in one of the heatsink-clamping columns 236 after beinginserted into the hole 249 of the other heatsink-clamping column 236,through the slot 252 of one compression block 152, the slots 256 (seeFIG. 21) of the plate spring 218, and then the slot 252 of the othercompression block 152, as described above.

The clamping screw 220 also acts to maintain the spring plate 218 inplace. The clamping screw 220 passes the slots 256 of the plate spring218 across the air duct 228 to prevent the elastic compression portion254 from being separated from the top surface 260 of the stack of theheat-absorbing portions 156.

The fan 128 mounted on the plate spring 218 blows cool air toward theheatsink 150 to forcibly cool the same.

FIG. 19 is a perspective view of the coupling structure of the mountcasing to the socket plate in the heatsink device of FIG. 18. Referringto FIG. 19, the coupling legs 226 of the mount casing 212 are slidablycoupled to the respective coupling supports 262 of the socket frame 214.Each support protrusion 230 is placed on and supported by thecorresponding support bar 222, and each coupling protrusion 232 isfitted into the corresponding coupling hole 224.

The support protrusion 230 horizontally protruding outward is supportedupward by the support bar 222 so that the mount casing 212 cannot movedownward. The coupling protrusion 232 is formed as a triangular toothand engages the upper side of the coupling hole 224 so that the mountingcasing 212 cannot move upward. As a result, the mount casing 212 issecurely coupled to the socket frame 214.

To slidably fit the mount casing 212 to the socket frame 214, themounting casing 212 is placed on the socket frame 214 such that thecoupling legs 226 match the corresponding coupling supports 262, andthen pushed downward.

To separate the mount casing 212 from the socket frame 214, each supportprotrusion 230 is pushed inward, as indicated by arrows “f”, to liberatethe coupling protrusion 232 from the corresponding coupling hole 224,and then the body of the mount casing 212 is lifted up.

FIG. 20 is a perspective view illustrating the heatsink being installedinto the mount casing to assemble the heatsink device of FIG. 18. Asshown in FIG. 20, the clamping screw 220 has a threaded end and is longenough to cross the air duct 228, as described above.

To fix the heatsink 150 to the mount casing 212, the heatsink 150 isinitially placed inside the air duct 228 such that the slots 252 of thecompression blocks 152 are aligned with the hole 249 and the screw hole250 of the heatsink-clamping columns 236.

After alignment of the slots 252 and the hole 249 and screw hole 250 iscomplete, the threaded end of the clamping screw 220 is inserted intothe hole 249 in a lateral direction, passes through the slots 252, andengages the screw hole 250. If the mount casing 212 is lifted up in thisstate, the heatsink 150 may be lifted up together with the mount casing212.

FIG. 21 is a partially cutaway perspective view of the heatsink deviceaccording to the second embodiment of the present invention. Referringto FIG. 21, the mount casing 212 is mounted on the socket frame 214. Theheatsink 150 is placed inside the air duct 228 of the mount casing 212.The heatsink 150 is fixed to the mount casing 212 by the clamping screw220 while its bottom surface contacts a heat-generating source “H” toexternally dissipate heat generated from the same.

The plate spring 218 is supported by the top ends of the compressionblocks 152 and heatsink-clamping columns 236, and both ends of the platespring 218 are fixed to the heatsink-clamping columns 236 by the screws258.

The bottom end of the elastic compression portion 254 formed in themiddle of the plate spring 218 elastically pushes the top surface 260 ofthe stack of the heat-absorbing portions 156 in the direction indicatedby arrow “F” to allow the bottom surface of the stack of theheat-absorbing portions 156 to elastically contact the heat-generatingsource “H”. At this time, the heatsink 150 moves downward with respectto the mount casing 212 by the elastic force exerted in the direction“F” so that the clamping screw 220 contacts the upper portion of theslots 252, which are slightly long in the vertical direction.

The slots 256 formed in both sloping sides of the elastic compressionportion 254, extending in the direction of the plate spring 218, allowthe clamping screw 220 to horizontally move upward and downward withoutinterference when the heatsink 150 moves upward and downward withrespect to the mount casing 212.

The heatsink 150 is movable downward with respect to the mount casingcoupled to the socket frame 214, and the center of the heatsink 150 iselastically pushed downward by the plate spring 218. As a result, theheatsink 150 is kept in tight contact with the heat-generating source“H”. As an example, even after an external impact on the mount casing212 in the upper direction, the heatsink 150 remains in contact with theheat-generating source “H”.

FIG. 22 is a partially cutaway perspective view of another heatsinkdevice according to the second embodiment of the present invention towhich the heatsink of FIG. 17 is applied. Elements having the samefunction as in FIG. 21 are denoted by the same reference numerals. Asshown in FIG. 22, the mount casing 212 is mounted on the socket frame214, and the heatsink 182 is placed inside the air duct 228 of the mountcasing 212. The bottom surface of the heatsink 182 is in contact withthe heat-generating source “H” to dissipate heat generated from theheat-generating source “H”, and the heatsink 182 is fixed to the mountcasing 212 by the clamping screw 220. The principle of mounting theheatsink 182 into the mount casing 212 such that the heatsink 182elastically contacts the heat-generating source “H” is the same asdescribed with reference to FIG. 21.

As described above, the heatsink according to the present invention isformed of a plurality of sheet-shaped heatsink plates, and theindividual heatsink plates are bound to one another to be radiallyspread out, thereby enlarging the surface area of the heatsink andincreasing its heat-dissipating efficiency. In the heatsink deviceaccording to the present invention, the heatsink is installed in the airduct, and cool air is supplied into the air duct by the fan, to therebyfurther increase the heat-dissipating efficiency. The binding force ofthe heatsink to a heat-generating source can be elastically maintained,which allows the heatsink to remain bound to the heat-generating sourceeven after an external impact.

In addition, by cutting out an upper portion of the heatsink plate,folding lines of the heatsink plate are shortened so that theheat-absorbing portions of a plurality of heatsink plates can be tightlyjoined to form a heatsink by a reduced force. The resulting heatsink hasa recession at the center of its upper surface. This structure allowscool air propelled by the fan to reach the bottom center of theheatsink, thereby further enhancing the heat-dissipating efficiency.Also, vibration and noise caused while cool air flows over theheat-dissipating portions of the heatsink are reduced.

While this invention has been particularly shown and described withreference to preferred embodiments thereof, it will be understood bythose skilled in the art that various changes in form and details may bemade therein without departing from the spirit and scope of theinvention as defined by the appended claims.

What is claimed is:
 1. A heatsink for absorbing heat generated from aheat-generating source, the heatsink being in contact with theheat-generating source, and dissipating the absorbed heat into the air,the heatsink comprising: a plurality of sheet-shaped heatsink plateseach having a heat-absorbing portion in contact with an upper surface ofthe heat-generating source and substantially normal thereto to absorbheat from the heat-generating source, and a heat-dissipating portionextending from the heat-absorbing portion to dissipate the absorbed heatinto the air, wherein the plurality of heatsink plates are arranged in astack, to form a heatsink plates stack and the heat-absorbing portionsform a center of the heatsink plates stack; and a pair of compressionblocks positioned to interpose the heat-absorbing portions of theheatsink plates stack therebetween and compress the heat-absorbingportions; and wherein each of the heatsink plates has at least onefolded portion that allows the heat-dissipating portion of theindividual heatsink plates to radially spread out by a force exertedupon the folded portion when the heatsink plates are tightly joinedtogether by the pair of compression blocks, to give the heatsink anelliptical column form.
 2. The heatsink of claim 1, wherein each of theheat-absorbing portions has a sheet form with a predetermined width andheight; each of the heat-dissipating portions extends from one side edgeof the corresponding heat-absorbing portion; the heat-dissipatingportions of neighboring heatsirik plates extend from the correspondingheat-absorbing portions in opposite directions; and the folded portionis formed at the other side edge of each of the heat-absorbing portions,so that, as the heat-absorbing portions of the stack of heatsink platesare tightly bound to one another, the heat-dissipating portions of theindividual heatsink plates are radially spread out by a force exertedupon the folded portions.
 3. The heatsink of claim 1, wherein each ofthe heatsink plates has an upper portion that is cut into apredetermined shape such that the resulting upper contour slantsdownward from the heat-dissipating portion toward the heat-absorbingportion, and wherein the heat-dissipating portions of the individualheatsink plates are radially spread out from the center to give theheatsink an elliptical column form having a recessed upper center. 4.The heatsink of claim 3, wherein the heat-dissipating portion and theheat-absorbing portion of each of the heatsink plates are formed as asingle body, and the upper contour of each heatsink plate after beingcut slants downward from the heat-dissipating portion toward theheat-absorbing portion and rises upward at both sides of theheat-absorbing portion.
 5. The heatsink of claim 3, wherein theheat-dissipating portion and the heat-absorbing portion of each of theheatsink plates are formed as a single body, and the upper contour ofeach heatsink plate after being cut slants dowhward from theheat-dissipating portion toward the heat-absorbing portion andhorizontally extends from both sidelines of the heat-absorbing portionto form a top end.
 6. The heatsink of claim 5, wherein each of theheat-absorbing portions has a sheet form with a predetermined width andheight; each of the heat-dissipating portions symmetrically extends fromboth side edges of the corresponding heat-absorbing portion; and whereinthe folded portion is formed at the heat-dissipating portions, so whenthe heat-absorbing portions of the stack of heatsink plates are tightlybound to one another, the heat-dissipating portions of the individualheatsink plates are radially spread out by a force exerted upon thefolded portion.